function y=Theorem4_1(u,mu,sigma,a,alpha,beta)
 y=(1-(u/a)^(1-2*mu/sigma^2))*(1-2*mu/sigma^2)^2*(alpha*beta)^(-2*mu/sigma^2)/((1-(alpha/a)^(1-2*mu/sigma^2))^2*a^(2-4*mu/sigma^2));
